What port number is used by LDAP protocol?

The correct answer is B. 389. The Lightweight Directory Access Protocol (LDAP) uses port 389 for unencrypted communications and port 636 for encrypted LDAP over SSL/TLS (LDAPS).

Submitted by klara.se· Mar 6, 2026Enumeration

Question

What port number is used by LDAP protocol?

Options

A110
B389
C464
D445

How the community answered

(57 responses)

A
2% (1)
B
89% (51)
C
2% (1)
D
7% (4)

Why each option

The Lightweight Directory Access Protocol (LDAP) uses port 389 for unencrypted communications and port 636 for encrypted LDAP over SSL/TLS (LDAPS).

A110

Port 110 is commonly used by the Post Office Protocol version 3 (POP3) for retrieving emails, not for LDAP.

B389Correct

The LDAP protocol, commonly used for accessing and maintaining distributed directory information services, primarily uses Transmission Control Protocol (TCP) port 389 for its standard unencrypted communications. Encrypted LDAP (LDAPS) typically uses TCP port 636.

C464

Port 464 is primarily associated with the Kerberos Change/Set Password Protocol, not LDAP.

D445

Port 445 is used by Server Message Block (SMB) for file sharing and printer sharing, not for LDAP.

Concept tested: Standard network port numbers (LDAP)

Source: https://learn.microsoft.com/en-us/troubleshoot/windows-server/identity/config-firewall-for-ad-domains-and-trusts

Topics

#LDAP#port numbers#network protocols

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